This really depends on your translation of the preamble. If you have used: Witnessth and whereas, then the final sentence is usually "NOW, THEREFORE the parties agree as follows:" For example:

WITNESSETH:

WHEREAS, ABC has entered into negotiations with Mr. YYY, who is the
registered owner of certain filed applications for patents and know-how relating to XXX;

WHEREAS, Mr. YYY has assigned ABC the rights for the production, marketing, use and distribution of the aforesaid patents and patent rights;

WHEREAS, ABC EUROPE GmbH is the licensee of XXX Technology for the licence area of Europe, Turkey and the former Soviet Union;

WHEREAS, ABC EUROPE GmbH has the exclusive rights for sale, production and further development of XXX in the licence area;

WHEREAS, ABC EUROPE GmbH has the option for all further developments and applications of XXX Technology;

WHEREAS, Interested Party is interested in getting closely acquainted with XXX Technology and in scrutinizing the marketing and production potentials of XXX technology.

WHEREAS, Interested Party undertakes the commitment not to infringe on ABC’s patent rights and/or patent applications—nor to challenge ABC’s applications for patents and/or patents; nor to institute nullity action against these patents and/or patent applications, either directly or through third parties, never to copy or produce the XXX, the XXX System and/or similar procedures based on them without a licence agreement or without obtaining permission in writing by ABC.

NOW, THEREFORE, in consideration of the premises and of the mutual covenants herein contained the parties hereto agree as follows:
Good luck!!!