If you use Move-Rx to create generic (not patient-specific) handouts of common exercise sets, you probably want to write in weights and durations that are specific to the person getting the hand out. Normally, when you drop an exercise in the selection box you are asked what weight you want to put in the text.
For generic handouts, where you want to write in the weight as you hand the patient their copy, leave the box blank and click the Okay button. You will get this:
Remember, that you can change the unit of measure in preferences so if you want Kg instead of Lb, click the “Manage my account” link (upper right corner), then the Preferences tab and under Units and Labels, set the units you use most. You can change them on the fly using the exercise editor on a case-by-case basis.