Very new player, very many questions

Makeshift lockpicks can be made from scrap metal with any hammering:1 item. Smash a locker and you get both, since the chunk of steel has a bit of hammering.
Make a bunch of them, they tend to break. It takes a while to get a door open, but is virtually silent, whereas the crowbar makes a CRUNCH that may draw zombies that are already close. Lockpicking also slowly levels mechanics, which is nice.

Donā€™t want to echo any of the same ideas as other people around here so Iā€™ll give you some things I do.
1.Looking through bushes near a forest is a great way to get emergency food. Also ant colonies.
2. Materials are easy to get when you break and disassemble stuff. Crashing a car can get you spare parts if you donā€™t have tools. Also a good way of breaking into a gun store.
3. Starting out, play it safe and try to keep at range. The knife spear is great for this as you can attack using (f) to attack 2 tiles away. Personally I enjoy using vehicles to clear out towns. A vehicle is a small price to pay for peace of mind.

If you have a high cooking skill cat food is a good food for preservation(canā€™t go off) and only needs water and meat.

Well, that shouldnā€™t be.

If itā€™s just water and meat it should have a spoil time. And it should be basically one day.

donā€™t forget that lots of handy supplies can be gotten early game by just (s)mashing all the things you donā€™t have tools to dissemble.

Pretty standard starting advice for LMOE shelter is to go out and grab a rock, smash a locker to get a pipe, make a makeshift crowbar, then use it to smash basically everything you donā€™t need and build everything you can out of the scraps.

The fact you were supposed to disassemble and then make your own tools was something I was ignorant of at the beginning. Once I understood how to get early game equipment, and how to raid at night, it got easier.