Hey there,
First up... welcome to @splinterlands & HIVE.
Starting out from scratch on HIVE is VERY daunting. The larger bloggers have their own little cliques and you're terribly unlikely to get noticed with just a giveaway. I remember giving away 10 STEEM (then ~$35) and got just 2 or 3 entries. #FacePalm
Don't get me wrong: giveaways are a great way of getting extra engagement once you have a larger following (or your giveaways become known and you get regular entries & votes - but that's gonna cost you a LOT more in cards to give away than the votes you're earning).
... so for now my 2 cents/unsolicited advice would be:
Try focusing on creating some cool content (discussing your battles, strategies, line-ups cards)... what you've learned and even what doesn't make sense to you (yet)... and yes, always use your #splinterlands tag. There are a few large curators like @monster-curator that will come around to your post - They check out all the #splinterlands posts manually (I am lead to believe anyway ;-))... and if you get a large enough vote from them, you'll find yourself on trending - which will then gain you follows much easier. Most people will go check out the rest of your blog for some form of consistency though before following you... so it might take a couple posts before you notice extra followers.
Even more NB than creating cool content: Engage other Splinterlands users on THEIR posts, leaving meaningful (or even ignorant/noob comments if you're legit asking newbie questions)... The Splinterlands community are (mostly) a bunch of really cool people and always looking to help the new guys out.
Oh yes:
If you DO still want to continue with the giveaways you should look at this 'random Hive comment picker' https://hivetools.herokuapp.com/picker/ ... it's a LOT easier than doing it manually assigning numbers to comments and using a 3rd app for picking the random number ;-)
P.S. Dropped you some upvote love and if my comment happens to win, please send the card to @wynella ... she's the reason I found your post anyway ;-)
i Really appreciate your comment. Thanks for the tip and thankyou for the warm welcome. Cheers🥂