any ideas in how to build a 75G lid for tank

As the title says I'm looking for ideas in building a lid for a 75g tank that I was given. So i'm hoping you guys have some for and a heads up I'm not that handy
Thanks in advance

It would really depend on what you're containing.

Usually you can make a frame out of 1 x2 in boards, with wire on top. But that's not going to keep in humidity if you have a BP or other humidity loving creature.

Solid wood can be fitted with a frame and plywood instead of wire, but is it secure enough? Do you need to fasten it to the tank or can it sit on top? For geckos, the weight of the frame will keep them in, but for a large python, it wouldn't.

Could router out and place some plexiglass.

For an escape proof lid. Make the top out of marine grade plywood. One solid piece you can cut doors into and add hinges and locks.

But looking at the inital solid piece, you can add 4 (one of each corner) internal blocks (one under each corner lip) and just run screws into the blocks from above (causes the aquarium plastic lip to be sandwiched in between).

if the cage needs to be high humidity, you can use plexiglass OR line the plywood lid with FRP.