Don't take this the wrong way, but in real terms you have next to no experience, and you have a
very long way to go before you have enough skill, experience, knowledge or ability. On site nobody is going to nursemaid you - they'll just sack you if/when you can't do the job, or you screw something up, or are too slow, and nobody will be there to answer questions for you. It's a tough environment, kiddo.
In any case, do you have a blue (level 2) or gold (level 3) CSCS Site Carpenter's card? No. This is meant to show a minimum level of training and knowledge - and for a larger site, run by a responsible main contractor it's no CSCS card, no job. You know, these days even labourers have to do a 1-day training course before sitting the CSCS Health & Safety test to get their green cards (and don't even think about getting a green card and then working as a joiner - AFAIK that was banned in 2016/2017)
As an example`of work, take a look at this thread; TBH I've had 2nd year apprentices who could have done this job
and known when to ask questions about the various gotchas (like that architrave the wrong way round, etc)
if they weren't sure - but they'd have known to lift the carpet nail strips before starting (because leaving them in place is a health and safety hazard, plus it limits access to the bottom of the skirtings for fixings into the sole plate, as well as making it difficult to ensure that the skirting is bent/scribed to the floor, if necessary). They would also have done me neat, closed-up middle of wall mitre joins with no gaps (ever heard of Mitre Mate, or even just PVA glueing and nailing the mitres and sanding afterwards?) which didn't require a ton of filler, and they'd have put me TWO screws in, one above the other (a single screw as you have done isn't guaranteed to hold the skirting plumb or limit cupping)
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This is extremely basic stuff that they get taught by the end of year 1 when they are with someone competent. And on the issue of site work a qualified man may have to put in 40 or more metres of skirting a day, including scribes and joins. Do you think you could do that? And do it well enough to get paid?
You might think I'm being harsh, but as a joinery foreman my job involves pushing the job along. On any job there simply isn't the time to deal with the untrained, unknowledgeable, slow or incapable (other than maybe the apprentices, and in their case it's because they are dirt cheap - many don't last). We often have a main contractor breathing down our necks with a QS (quantity surveyor) in tow who will pick-up every defect and use them as an excuse to withhold payment - so if someone isn't pulling their weight you warn them first, then if they don't improve quickly you fire them (let's call a spade a spade and say that I never "let people go"). Bear all this in mind if you are thinking about site work
I notice you didn't ascertain what the wall was made from. FYI in order to get a fix you need to ascertain if it is dot and dab onto masonry (so long screws and plugs) or a stud wall (on which case locate the studs and sole plate). Caulking because you can't find a stud to fix to is a fail on an NVQ test.
Finally those screw holes need to be filled with 2-pack wood filler, mixed on a scrap of skirting/plywood/etc and applied with a flexible stopping knife. Once set hard (maybe 1 to 2 hours) you sand it back with a small sander such as a 1/4-sheet orbital sander, because you cannot hand sand 2-pack. Also see you bodged the filler around the architrave joint...
So how long did all this take you?