With the second part, I would use a checkbox control rather than a text box.
I would link it to a cell  somewhere and in the linked cell put the formula
=CL2=3. This cell will show  true or false depending on the value of CL3 and
the checkbox will be ticked or clear accordingly. In this case you must
disable the checkbox as, if it is clicked the formula in the linked cell
will be overwritten.