How do I pass in parameter values in Bamboo job like the way we do in Jenkins?

[Sugat_Sapkota]

I am migrating Jenkins job to Bamboo. My Jenkins job is parameterized and the parameters take values defined in the codebase it downloads. 

How do I parameterize those variables in Bamboo similar to Jenkins. For example, these are the paramters used in Jenkins.

1) BRANCH_TO_BUILD : We pass in the branch name that needs to be downloaded.

2) specsToRun : we provide particular specs to run. For example, specs/smoke-test.js

3) environment : It gets values from environment.json file.

How do I do similar thing in Bamboo and run my job successfully ? Any idea would be appreciated.