The straps it comes with are only good for a telegraph pole type tree. I have fallen out the tree twice trying to set the straps.
On the subject of straps, IME nothing comes with adequate straps, but it's easy enough to get decent ones separately, and the army-surplus spanset-type straps are long/tough as they come.
It's also recommended to use two strap sets to put up a seat.
The first is secured as far up as you can reach when standing on the ground (or you can use two long lengths of rope or nylon webbing, attach them to the seat before you prop it against the tree, cross them over behind the trunk, then tie the ends to the ladder). Either way, this will secure the ladder well enough to let you climb up, attach and tension a ratchet strap.
When fixing the ratchet strap, once again it's better to attach the "plain" end when the seat is still on the ground, tying off the loose end to one of the rungs. After you've secured the seat with the first strap, untie the end of the second strap, loop the plain end it around the back of the trunk, then carry it up to the top of the ladder with you.
If it's too short for that to be easy, temporarily tie on an extra length of rope or webbing for convenience: anything so that you don't have to lean out from the seat to get the job done.
Short of being very silly with a rifle there can be few ways of doing yourself more harm when out stalking than falling from a seat, so it really is worth spending a little extra time and money to avoid accidents.
Where the ground is prone to being soft but you can get close with a vehicle, and even if its just a spot where you expect to put a seat now and then, it's worth bedding in a cheap garden paving slab as this will stop the foot of the ladder sinking in or rusting. It's relatively inconspicuous too, and not worth the effort of stealing, but it will give you your own personal bit of hard standing just where you want it.
HTH.
