Right on for using your compost mate. I love using my compost after a couple of years. One thing to watch out for its bugs. Make sure it is all completely composted. And yes you can for sure add sand to your mix to allow drainage.. nothing wrong with that. Just make sure its sterilized. You can also use perlite too which is effective.

Nutrients.. i personally like to use supernatural nutes.. Gro terra for veg and bloom terra for flowering. Its super simple to use. 1/2 tsp per gallon in veg and then 1 tsp per gal in flower. You can feed every watering, but you will probably get some salt mineral buildup in your soil... So its best to do like feed/feed/water or feed/water/water.

Start adding nutes very slowly... Start really light in like the 2nd week of veg, and then slowly work your way up.

Good luck mate. Hope this helps.