Basically as follows. An installation at the airport concerned will send signals providing lateral (localiser) and vertical (glideslope) guidance. This will be interpreted by instruments in your aircraft that will then, provided properly set up and within operational range, provide visual indication to the pilot of your position relative to the design approach path.
If using an ILS, ATC may ask to to fly a procedural approach (possibly starting with a hold) which will then require you to follow a published procedure to 'intercept' the ILS. Alternately, you may be given radar vectors to intercept.
When intercepting, you will first intercept the localiser, which requires a turn onto the appropriate approach heading, allowing for wind correction, adjusting heading as required to follow the localiser needle. The glide path will be above you at that point, and will be intercepted from below. When cleared by ATC to do so, you will follow the glideslope down to decision altitude/height. At that point, you have to go around if you are not visual with the runway.
You do see a lot of pontificating on forums such as "dont try this without training" but in the case of an ILS in IMC, it really is the case - you need both good training and good currency to do it safely.
Thank you
Makes sense.
Of course, I'd never try something without being instructed first. It's my full intention to get my IR(R), probably this year, but just saving the funds