Comment by Scalestein

There are three knots I use that have covered all my needs as a casual camper:

Taut-line hitch

Sliding knot for fastening loads or setting guy-lines https://www.netknots.com/rope_knots/tautline-hitch

Bowline

Essential general knot for tying a loop. https://www.netknots.com/rope_knots/bowline

Square Knot

Used for joining ropes or just an easy to unite knot. For joining ropes you could do a sheet bend which is stronger https://www.netknots.com/rope_knots/square-knot

https://www.netknots.com/rope_knots/sheet-bend

There are a billion options so I recommend just picking a few and practicing until you can tie them quickly without references. You'll start to understand hope knots in general work and be able to pick up other knots much easier.