Beginning the cementation procedures :

 The surface of the post is cleaned with a cotton pellet soaked in alcohol and then receives several layers of a silane agent, followed by a gentle jet of air for the volatilization of any solvents.

 The bonding procedures are performed at the tooth surface. Initially, the adjacent teeth should be protected with a mylar strip to prevent any inadvertent contact with the phosphoric acid.

⛔️ The acid is applied at the depth of the root canal to ensure a consistent etching application thus minimizing the presence of the bubbles which would result in poor etching.
It is important that the conditioning is extended over the entire surface to receive adhesive, cement and composite resin during the core build-up.
⛔️ Do enough rinsing and ensure that the root canal is completely absent of acid remnants ( you can use irrigation tips to reach the full length ) then the excess moisture is removed with absorbent paper points.

 A dual-cure adhesive is applied to the dental substrate with the aid of micro-brush compatible with the diameter of the canal.
The entire area that will receive the composite, as well as the entire surface of the post, should be coated by the adhesive and the solvents are volatilized with gentle air jets.
⛔️ The surplus adhesive is removed with absorbent paper points and the solvents are volatilized with gentle air jets.

 Dual resin cement is then manipulated and applied to the canal surface by means of a syringe or lentulo drills. 

With the canal properly filled the cement is applied to the post that is inserted into position and subjected to digital pressure until it reaches its predetermined height ( try to do that very quickly to avoid the polymerization of the cement as it can prevent post insertion to the full length ). 

⛔️ Remove excess unpolymerized cement then light curing is carried out.

Now you can construct the core build-up either by the incremental addition of a light-cured composite or whatever the technique you prefer ( will talk about that later ).

In the following link, a video demonstration explaining the full procedure
Fiber post cementation