Redesign graphics in a professional way

I can do the work if I can just be shown how to do it. There is a pot file but editing it isn't working. I don't want to change the language of the site. I just want to change some of the strings from the terms they use in the UK to terms they use in the US. For example, in the UK (it seems) that they use the term "transfer type" where in the US the term doesn't sound right. "Trip type" sounds more natural and appropriate. Similarly, "return" in the UK doesn't sound as appropriate as "Round trip" for the US. I just want someone to get on zoom with me for maybe 30-60 minutes to tell me how to edit these strings so that I don't need to go through the code and edit them everywhere. I'd like to do this right away.