There is a date range setting for each Benchmark Window that is determined by the district Head Admin. The benchmark window needs to be open in order for students to take a test. Only one benchmark window at a time should be open.
Benchmark tests are only administered on-grade. The easyCBM program was designed for students in grades K-8th grade and it will not let you administer an off-grade test. If a student is not performing at grade level, then progress monitoring measures should be utilized instead of the benchmark tests. 
For more information on how to open and close benchmarks click here.