Ahoy Akelu. Ok so firstly, what medium are you using? As this will determine what nutes to use.. Flower/bloom nutes will be no good during the veg period (the growing period) as they contain very little nitrogen, an element plants needs to grow. Flower/bloom nutes are used during flower/when your plants start to bud, so you'll need a growth/veg nutes while it's growing. Read the dosage on the bottle for how much to feed (example, if they say use 5ml/L this means 5millalitres of nutes per 1litre of water), usually half that strength during the first couple of weeks once the seeds pop above the surface and just water before. Feed your plants when the medium is drying out, you don't want it soking wet all the time. But again this will depend on the plant and the media you use. As an example, I'm growing two outside in pots atm in 25L & 19L pots and I only need to feed them every 5-6 days. As for potting up (up sizing), once you can see quite a few roots poking out of the holes in the bottle of the pot or if the growth of the plant slows down then it's time to up size.. Hope this basic guide helps matey. Get started and start a grow diary on here with pics and I'm sure you'll get more help/advise along the way All the best