There is an important point to be considered in resource assignments in MS Project. That is how many hours a day the resources will be allocated to their assigned job.
If an assignment is made as follows, this indicates that Ali will spend full time (8 hours per day) on the following dates. In other words, it will not be possible to be appointed to another job at that time.
However, our resources often do not work this way; They will look at 2 different jobs during the day. In other words, it can devote 4 hours a day to one work and the remaining 4 hours to another. To plan such situations, we need to change the unit values of the resources. In the example below, Ali will do a 10-day job, separating 4 hours (half time) every day.