how to make a User form that auto-populates info from a selected sheet

Hi there,

firstly id like to say how helpful this forum has been so far, and also apologize if this is already a question on the forum. I have tried searching for what I'm after but I've not found anything, probably down to the way I'm wording the question.

I'm working on a project to help deal with holiday requests and allow users to see what holidays they have taken and remaining days, further to this I also want to implement a way to request future holidays.

The section I am currently working and stuck on is: sending a response to a request using a userform.

my idea is to have a dropdown list or similar to select the individual that is requesting the holiday (each user has their own sheet where the info I want is to be pulled from)

This list then auto completes some parts of the form, such as, name, total holiday allowance and current remaining of this allowance. all this info will be on the selected users sheet. if this is possible i then want this to add the approval to a list on the sheet of the user.

i hope this made sense and if not please let me know and i will do my best to clarify my question. ( this seems to make sense in my head, which probably means it wont make sense to someone else )

ive attached my current workbook if you need to see what i am trying to put in words.

Im using Excel 2013

many thanks in advance