Acquired building ; the cost $200,000 ; with estimated life 40 years. It will be depreciated over 40 years using straight line depreciation. Salvage value $20,000.

How do I journalize this?

I have
Cash $200,000
Building $200,000

The journal entries are only for 1 month

At the time of purchase,

Dr. Building 200,000
Cr. Cash 200,000

To record purchase of building
Building Dr $200000
Cash Cr $200000
(To record purchase of building on cash)
Explanation|
Increase of asset mean debit and decrease of asset dictates credit. When purchase of Building occurred. Building is asset which will increase or added to business. Cash is also a asset it will be decreases, hence it will be credit.
At the end of the year journal entries for Depreciation will be Depreciation Dr Accum-Dep Cr. However it is not asked in the question but mentioned.