Once you've completed the crimping it's time to melt the adhesive lined heat shrink. I am using my heat gun in this photo but not on the highest setting. I've found that with adhesive lined heat shrink you can melt it too fast and not get a proper adhesive melt on the adhesive lining. A slower melt will produce better adhesion of the insulation to the wire jacket.
TIP: Please do not use open flame on these expensive terminals. It leads to uneven melting of the adhesive, distortions in the insulation and can lead to leaks. Use open flame only as a last resort. A heat gun with consistent predictable heat is the proper tooling for these terminals.