I have all my coins in on an online trading site (paxful) (low volume)

I plan on making a large investment very soon, and want to safely store all of my coins
I.E I basically want to drop a couple thousand, and keep them in the safest possible way, where I can revisit them in 5-10 years or so and reap the benefits, or cry about the loss.

What is the best way to do this, and what's the best way of ensuring a backup?

How do you currently store your coins

thanks in advance for any inputs