administrative data - adding

Dear Team,

Server Details: OS-CentOS Linux 7 (Core),  >PHP- PHP 5.4.16 ,DB- 10.2.32-MariaDB,Webserver-Apache/2.4.6 (CentOS) ,Ocs-ersion -2.5

i am trying to add addition field in administrative data like purchase date, value and vendor name.

i am following this link to add field - https://wiki.ocsinventory-ng.org/04.Management-console-and-its-advanced-features/Managing-administrative-data/

Field successfully added but i am unable to make entry in field,screen shots shared below for your reference

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field added but unable to add purchase details and default option not there like computer column,plz advice how to do ?

some one plz share the proper document to add administrative date