Hi. First you need to setup the numbers.
State 1
1. Wait for x amount of time, ie 1 second. Action: Wait. On finish, go to state 2.
State 2
2. Int variable. Action: Int add.
3. You need to convert the int to a string. Only strings can be displayed. Action: convert int to string.
4. You need to display it. Make a uGUI canvas with some text. Next, to change it with playmaker. From the ecosystem, download the ugui actions package. Then use the action: set ugui text (I think that is the name).
5. Check to see if your number has reached 100 (or 50). Use action: Int compare. If equal or greater than 100 (or 50), then go to a third state (maybe called finished). If less than, go back to state 1.
State 3
Empty state for finish.