Hit Command T and with the type tool selected, click and drag out whatever size frame you need.
Not going to help if you click into an already existing text frame.
It's very hard to learn a program as complex as InDesign on your own by asking scattered question.
I highly recommend what I think are two of the best resources for learning InDesign:
1) Sandee Cohen's Visual Quickstart Guide for InDesign. Available in different editions for different versions of InDesign. Here's a link from Amazon US:
2) David Blatner's InDesign Essentials videos at Lynda.com. Free trial for 10 days.
Okay well just make a new layer. You cant make a box within a box, at least I've never tried that.
You cant make a box within a box, at least I've never tried that.
You cannot make one 'inside' (= on top of) an existing text frame because the cursor will select text if you drag it on top of text.
But if you want to end up with a paragraph inside a framed box inside a current story, just cut out the text and paste it with nothing selected, so it appears as a new, independent text frame. You can give this new frame a border and other formatting such as a background color; then cut it again. Click with the text cursor into the running text where it should end up and paste. Done.