I'm not familiar with the module, but seeing as it'll be your little brother's first time playing, I'd recommend the following:
Focus on the story, and your brother's involvement in it
This is probably the most reliable way to hook someone on D&D
Spark their creativity
Keep combat simple
Use that DM screen for cover!
Don't be afraid of fudging rolls by enemies if your brother is not faring well.
For instance, I would not let enemies score critical hits on the PC.
It's hard to get hooked on a game when (while at low level) an unlucky crit from an enemy that takes them from full HP to unconscious, and they're the only player.
Make at least one NPC companion to support your brother's PC
Use them to fill whatever gaps in skills/spells/abilities, that are needed in the module, and that the PC doesn't have
Basically just use them for: making sure your brother's PC doesn't die, skill checks the PC failed, skill checks the PC can't succeed at, etc.
Always let the PC take lead; NPC is a safety net.
You're not playing a typical campaign, it isn't Adventurer's League, and you have an explicit goal of getting your brother into the hobby. Just focus on him having fun with the scenario, and be lenient with difficulty. Soul-crushing reality can wait until after they're hooked!
You don't know what fear is until you've witnessed a drunk bird divebombing you while carrying a screaming Kobold throwing fire anywhere and everywhere.
I need some tips on how to play as me being a first time DM and my 12-year-old brother as the player.
I have a starter set with the campaign "Mines of Phandelver" .
I have a limited experience on being a PC myself but i want to get my brother into it.
This campaign will be a DM:1Player ratio so please give advice.
I'm not familiar with the module, but seeing as it'll be your little brother's first time playing, I'd recommend the following:
You're not playing a typical campaign, it isn't Adventurer's League, and you have an explicit goal of getting your brother into the hobby. Just focus on him having fun with the scenario, and be lenient with difficulty. Soul-crushing reality can wait until after they're hooked!
You don't know what fear is until you've witnessed a drunk bird divebombing you while carrying a screaming Kobold throwing fire anywhere and everywhere.
Watch some youtube videos, such as Eric Watson's campaign in the LMoP. It'll help you with ideas and finding your own style.
Perpetually annoyed that Eldritch Knights can't use Eldritch Blast, Eldritch Smite, and Eldritch Sight.