Oh.... you can record in a sense in that manner BUT you do not arm the track and play the notes like you would with a keyboard attached.
You must use either STAFF VIEW or PIANO ROLL VIEW (PRV) and you simply "write" the notes in by clicking on the staff or PRV with your mouse. You can drag notes around and build chords and do all sorts of things. You do not need to arm the track to use this method. It is slower to work this way but it's a very workable solution if you don't have a keyboard/controller.
I have heard one fellow here who built an entire symphonic production around this method.... it was about 5 minutes long and quite amazing. violins, cellos, double bass, horns, percussion, the entire orchestra....really a nice piece of work... kinda wish I knew where to find it to let you hear what CAN be done using the "point and click" method of composing.
ADD: set the tracks up so you can hear the synth sound when you click the keyboard..... now highlight the synth midi track and select VEIW.... choose PRV or STAFF. Clicking on either should insert a note AND you should hear it play. Proceed to build the part you intend. PRV and STAFF are slightly different and everyone has a preferred one to use. I like Staff better because I was taught to read music on a staff.
You can edit by dragging notes right and left, up and down, change note values, add and delete.... so have fun.
It is easier to enter notes with a keyboard.....