今日(きょう)友達(ともだち)とポーカーをした。
今日私(わたし)は友達とポーカーをした。
A couple examples, and there are a number of other sentences that will work. You could use が instead of は in the second one. The problem with translating a sentence like that without context is that there are several possible Japanese sentences that imply different contexts.
I think the first one I gave is the most neutral, and omitting the "I" is usually quite natural. In context, however, this could also mean someone else played poker with their friends.
The second one feels like a conversation where 2+ people are discussing their activities - "I played poker with my friends (as opposed to what someone else was doing)". If you replace が with は, to me it now sounds like the answer to a question - "Who played poker yesterday?" "I played poker yesterday, with my friends." は vs が vs no particle is a subject that's tricky to explain, and if you need help with it, it's probably best not to rely only on my explanations
今日は友達とポーカーをした。
This one attaches that sense of contrast to 今日 instead, so "Today (as opposed to another day) (I) played poker with my friends."
I digress, and this was maybe TMI.
Back to your actual question, 今日 sounds most natural first, and I remember a Japanese teacher at some point telling me that words for
relative time, like 今日 or 明日(あした) but not 三月(さんがつ) generally come at the head of the sentence without a particle (unless は is necessary). The rest of the sentence will usually go subject, object, verb. This is flexible, and if you reverse the subject and object the sentence will still make sense, but most commonly the order is SOV.
To add in "I lost", one possibility is: 今日友達とポーカーをしたけど、負(ま)けた。
jemstone: For stuff like sports and games, generally する or やる is used.