Thread meta description

[visifilmailt]

Hello, where can I change the topic description?Meta description.now shows the description of the first message of the topic.
now i see

"<meta name="description" content="Belgrado „Crvena Zvezda“ ekipą dėl šiurkščių Finansinio stabilumo ir sąžiningumo taisyklių (FSFPR) pažeidimų nubaudė Eurolyga." />"

i want to show lik this:

"<meta name="description" content="thread tags, and two or three me words example:Euroleague Basketball, basketball, world basketball" />"

where i cant change this code?

 

[BattleKing]

this will be taken out of the first post, nothing you can change