First grow

Hello everyone, this is my first ever grow, and I have 0 experience :). I am facing some problems with N deficiency according to the looks of it. It started with the old leafs and now it keeps spreading, 4 leafs went completely dry, and the others seem to be on the way. At the beginning I thought that not using any nutrients is a good and easy idea, specially because I have no clue what to use, but when the N deficiency started 2 weeks ago I started using the mentioned nutrients, but still it does not seem to be helping, it even got nutrients burn although I'm using much less than the recommended amounts. For the soil I followed RQS advise for Autoflower and made a mix of ( 3 parts peat moss, 3 parts compost, 2 parts perlite, pre-wet, 1 part vermiculite, pre-wet). I only used tap water and I don't have a PH meter. Any comment is appreciated, and forgive my noobness :D