I completed this course earlier in the year.
The assessor will come into school and literally stay nearby and watch what you do. They were chatty and friendly to start with and told me to just do what I normally did and they would see what evidences in my folder they could sign off.
Things like 'promote health and safety in the setting' or words to that effect, could be witnessed by you just saying to a child, 'sit on your seat properly on you bottom', or don't run with scissors. Ale to communicate appropriately with children can be seen by you naturally chatting, getting down to their level and listening etc.
There are numerous things like this that they will tick off, just by spending an hour. Hopefully the visit will coincide with you doing something interesting. I was lucky my teacher set it up so I was doing some group reading. I actually forgot she was watching.
At the end, she will show you what she has ticked off and maybe write up a sheet for you with some personal observations too. Show them any wall displays you have done, or any resources you may have out together. The more you can get signed off the less you have to do yourself!
There are usually two placement visits. They aren't like an inspector, it is very informal and relaxed. They may not even have experience of the course, but are just a qualified assessor.
Best of luck.