There are a few things to check for when attempting to enter the @ symbol then the measurement/distance i.e. @4',4' when drawing rectangles or dimensioning etc.
- First check if dynamic input is on.This can be done by clicking the F12 key from the keyboard or going into the drafting settings > Dynamic impute tab and make sure "Enable Dimension Input where possible is checked.
- Verify that the system variable PICKFIRST is set to 1
- Verify which template you started with. Imperial, Metric or Global.
If you still are not able to use the @4',4' then this can be an issue with your scale factor for your primary units.
You can set this in your current dimension style by typing ddim at the command line or from the Home tab on the ribbon > Annotation pull down and click on the dimension style manger icon.
Click on the style that is currently being used and then click the Modify button. From the Primary Units tab change the scale factor from 1 to 12. You should now be able to impute the feet symbol to enter in a distance or measurement.