Two referenced fields in one field and filtering contacts from one company

Apologies if these have already been asked, but I want to take the first name and last name of a contact table and insert them into one field of another table. I have tried dragging and dropping them but this gives me the two names with no spaces ('First Name' + 'Last Name'). What do I need to add to the formula to include a space between the two names?

Secondly, but related to the above, how can I filter a form so that when I add a company to a sales form (from a referenced company table), it will only show me a list of contacts (from a referenced contact form) I can choose that are employed by the referenced company.

Hopefully this makes sense and many thanks in advance.