@alannamckenna What I was actually going to contribute to this I've already answered to you in your other post on the Welcome forum. Hopefully you find the info in there useful :)
To answer the more specific questions -
People can't usually tell if you're new unless you act really nervous. That said there is an expression called "cottontail" which is used to describe people with tans but white bits where they frequently wear swimsuits whilst tanning.
Find somewhere that is a respectable distance away from other people so you don't invade others personal space.
Simply get yourself set up (towel, sunscreen, parasol if you have one), food etc) so you're comfy and strip to your swimwear - then strip off at your leisure when you realise you are the odd one out lol Do please make sure you take a higher SPF for your areas that haven't seen the sun yet. It's possible you use an SPF 15 or 30 for your skin normally, but for the bits that are usually hidden please please use an SPF50 for those regions. The last thing you want is sunburn in places that never usually see the sun.
It's unusual for people to stare - a common theme that is promoted among nudists is that it's ok to look to notice where people are but it's rude to stare at them. It can also sometimes be that someone might be reading but you think they're staring when they're probably not. If you're uncomfortable then it's perfectly ok to slip your costume back on or to change the angle of your towel so it's harder for that person to look at you. As for whether you can take more affirmative action depends on you and the beach you are on. If it's an official one then there might be people there in an official capacity who can help out. Another option is to see if you can post online in a nudist forum (one which is specific to your local area) to see if there's a group going on the same day as you, in which case you could join in with them which will then give you safety in numbers.
And honestly don't worry about how you look in or out of your swimwear. I have seen all sorts of differently built bodies over the decades, from young to really old, and one thing you learn as you get more experienced is that whilst we all have anxiety about how our bodies look to others, this is exclusively in our heads. Nudists are the most welcoming and accepting group of humans I've ever had the privilege of socialising with, and I'm someone who doesn't make friends lightly. I hope this helps with your own thoughts but to give you an anecdote of personal experiences when I was with my last ex she developed breast cancer in 2012 and spent most of 2013 going through surgery, chemo etc to help her recover. The surgery involved the removal of tissue in one boob and a reconstruction which involved taking muscle from her back to replace the tissue that was removed. By 2014 she was back on the nude beaches in Spain, and when we were going to a local sun club in 2017 / 2018 she had no issues with going bare and everybody there accepted how she looked with good grace.
To answer your last question - my first time was solo, I've had many other times solo but I've also been nude with an ex and various friends over the years. I've also been in situations where I was the only one nude among friends, as well as being nude with friends where I was with several who were nude and several who were clothed. So it's a properly mixed bag for me.
