At this point, you know how to get from one point to another, both tactically, so you minimize your risk of being seen while maximizing your chance of arrival, and in such a way that you arrive at the correct destination at which you were aiming.
But at some point, on anything over a day, you're going to need to lay up, and give people a chance to eat, sleep, poop, et cetera.
That's what a patrol base is for.
The world isn't perfect.
But in a perfect world, you want a spot that has the following attributes:
1) Good all-around visibility
3) Multiple avenues of approach and exit
5) Unappealing to others for occupation or reconnaissance by fire
6) Near water but not right by water
Most of these are mutually exclusive, so you'll be making compromises between different aspects in almost all situations.
You can (and should) look over the selection criteria from the Ranger Handbook
(1) Selection Criteria.
• Select Terrain the enemy would probably consider of little tacticalvalue.
• Select Terrain that is off main lines of drift.
• Select difficult terrain that would impede foot movement such as anarea of dense vegetation, preferably bushes and trees that spreadclose to the ground.
• Select Terrain near a source of water.
• Select Terrain that can be defended for a short period of time and thatoffers good cover and concealment.
• Avoid known or suspected enemy positions.
• Avoid Built-up areas.
• Avoid Ridges and hilltops, except as needed for maintainingcommunications.
• Avoid Small valleys.• Avoid Roads and trails.
In short, something that's good for you, bad for anyone that doesn't like you, but not obviously the exact place where he'd think you'd be if he was you.
There is a training film that may help.
And, surprising no one, the Pythons stumbled over the essence of the patrol base concept: Don't be seen.
As the opening diagram of this post displays, once you pick your spot, your team, of whatever size, needs to conduct a thorough and slow reconnaissance before occupying it. Because a spot that looks good to you probably looks good to people who don't like you. It would be awkward to try and move in if they're already at home there, wouldn't it?
So well before it's dark, pick the spot. Observe it. Investigate it thoroughly close-in, and working outward. Best if you don't trample an obvious path to it from your line of progress, which is rather the same thing as saying "Shoot up this area" to anyone who comes along after you've moved into the neighborhood, and finds those signs.
Once you move in, set up your group in such a way that they're watching, and can watch, 360° around at all times. One or two persons/teams/whatever will be doing exactly that, when the rest are doing admin tasks like reporting in, eating, cleaning weapons, or answering nature's call. If everybody flakes out or goes to sleep, it's okay - if you want to risk none of them ever waking up. If you like staying alive, someone is always on watch.
Units doing this under real-world conditions learned to assume they were always under observation. So they'd occupy a likely spot, and make the fullest appearance of settling in.
Then, once it was too dark to tell, they'd quietly gather up, move a few hundred yards away, do it all over again in the dark, and then settle in for the night in the second spot.
Nothing, I'm sure, warms you heart more than having someone loudly attack your old position while you sit in a new place and watch the fun, not being there to receive someone's worst doings. Any patrol means you're either predator, or prey. Try not to be prey.
Once you occupy the patrol base, there are priorities of work to accomplish.
1) Security - continuously
This will include creating hasty fighting positions, controlling access in/out (should be a single point in the perimeter circle), and making sure everyone knows the direction they're responsible for, for watching, and if necessary, for shooting.
2) Withdrawal - could become necessary at any time
Everyone needs to know the signal, direction, and where to go
4) Mission planning - for continued operations
5) Maintenance of weapons and gear
No more than 25% of your weapons down at any one time
6) Water re-supply
Make sure anything collected by anyone is treated or purified before anyone drinks it
8) Rest vs. Alertness
Who's on, and who's off, and when they change
9) Re-distribution of supplies/equipment
10) Personal hygiene and sanitation
Slit trench(es) for poop, and urine cathole(s) should be selected ( away from water point) and designated to all team members, and constructed. And filled in well afterwards, for all departures except those under fire.
That's pretty much the order things should follow, and anything ought to be done in such a way that if things go pear-shaped, the entire group could be gone in sixty seconds.
If not, you're doing it wrong, and you'll eventually pay for the laxity.
The patrol base may be occupied for just a brief rest halt, overnight, or for several days. However long, it should be constantly improved inside, and remain unknown or noticed from outside, until departure.