The KingdomOfHeaven is not so much a place as it is a state of existence.
We are born into the KingdomOfHeaven as NewSpirit beings by GraceThroughFaith in Christ Jesus. Doing so, makes us eligible for SpiritBaptism.
Heaven is the SpiritRealm. We enter into the SpiritRealm in the NewBirth.
Not understanding that relationship with HolySpirit - being in Him and Him in us - is major doctrinal error explaining the weakness of many believers.
Many believers go about searching in groups or churches or through gurus to experience the KingdomOfHeaven not realizing that it is in them and must be experienced and manifested by faith.