CA35 The other approach you can try is to gauge the headspace (I.e. gap between the coffee puck and the shower screen). The maximum space you want it to be is about the same as a small coin (e.g. 1p).
To test this prepare your puck like normal and gently place a coin on top (if your shower screen has a protruding bolt in the middle then you’ll need to place it off to one side, if not I’d put it in the centre). Dry the shower screen and then lock in your portafilter. Take your portafilter out again and look where the coin is. If it has been pushed into the coffee you’ve got too much in your basket, if there’s no mark at all you can increase your dose next time, if there’s a very light imprint then you’re about right.
Taste is the important thing though, and there’s nothing wrong with using a lower dose in a basket. Soggy pucks are just an aesthetic issue. The coffee expands when wet, so at the maximum dose this means it pushes against the shower screen, and at the end of the shot when pressure is released through the 3 wave any excess water exits, leaving a dry puck. With a lower dose some water remains and the puck is soggy.
Never forget that taste is king with coffee though. There are lots of tweaks (and dare I say it rituals) that many of us do, but always check you can actually taste the difference. It’s very easy to forget, and go down a rabbit hole of expensive accessories and palaver that make your workflow tedious and don’t actually make a difference that most of us can taste.
As you said you’re a beginner, to be in the right ball park (once you’ve set your dose), keep grinding finer until you’re getting a 1:2 ratio shot in 25-30s (I.e. if you use 15g of coffee you want 30g of espresso to take 25-30s from when you turn the pump on). Depending on your coffee you might want to extract a bit more or less based on taste and your preferences, but you’ll be starting in the right ballpark. If it’s coming out too fast you need to grinder finer, that’s almost always the issue. In a pressurised basket the coffee grind is less important as the basket restricts the flow, but with a normal basket the coffee does this. It’s normal to need to tweak the grind slightly. Don’t worry this will become second nature.