Number recognition

I am new to Trados and have just practising what I have learnt in the Webinar I participated in last week. Please excuse any questions that may appear 'silly' to an experienced user.  I am at that stage when I am getting to grips with some of the concepts of a CAT tool.

I am having a few problems getting my Trados (Studio 2017) to behave in the same way as it was shown in the Webinar. I understand it handles number recognition well and underlines the number in blue which means you can "CTL ," to transfer a number over in to the TT in the format of the TT country. However, numbers in the files I have imported into Trados are not underlined in blue in editor mode and  so "CTL ," does nothing whatsoever. I have checked Fields and setting and numbers box is ticked (along with variables, times dates etc.) and so I cannot understand why it doesn't recognise numbers thus not allowing me access to the facilities available with that tool. I appreciate that with my very limited knowledge of Trados, I may be missing something very fundamental here.  Is there anybody who can help?

Also (changing the subject), just to check my understanding: you can only switch on 'autosuggest dictionaries' and 'UpLIFT' when you sufficient TU's in your memory but not before? 

Thank you for your help.

Kind regards,

Gill.