The 19-year-old came off the bench during Rhinos’ Dacia Magic Weekend defeat by Wigan Warriors.
A specialist prop, Hallas has started at hooker in Rhinos’ last three academy games and slotted in there during his senior debut.
“I usually play front-row, but I have been learning from the likes of Rob Burrow and Beau Falloon and everyone’s been giving me pointers and little tips,” he said.
“Everyone has been really helpful and I think it has been quite an easy transition to make, because everyone has been really positive. No one’s been slamming down on me, everyone’s been really patient and Mac [coach Brian McDermott] has been giving me a load of tips, as have [assistant-coaches] Barry Eaton and Chris Plume.
“Obviously the change from prop is hard because of the massive difference in the game, but it’s a challenge I am looking forward to carrying on with. It would be nice to get a couple more appearances this season, but if it doesn’t come I am just looking to really get to know the position of hooker and carry on with the 19s.
“Hopefully I can string some good performances in there, hopefully Mac sees that and then we’ll see where I go from there.”
The Rhinos rookie is a cousin of Graeme Hallas, who played professionally for seven clubs before spells as Leeds assistant-coach and team boss at Hunslet Hawks.
Of his debut at Newcastle United’s St James’ Park, he said: “It was a really good experience. It was good just getting out there. I have been training for a few weeks now with the first team and I never really thought I’d be making my debut at the Magic Weekend.
“But the whole experience – the build-up, the travel on the coach and everything about it – was massive for me and something that’ll stay with me throughout my career.”
Hallas, who has featured in England youth and academy squads, joined Rhinos’ scholarship in 2011, after taking up rugby league at the Stanningley community club.
Team-mates Ashton Golding and Jordan Lilley are also Stanningley products and Hallas said: “Every team I have played in – school, national, county or whatever – I have played in with Ashton.
“I met Jordan at Stanningley when I was 12 years old and from the team we had then there’s some lads at Bradford and places like that, where they are coming through as well.
“We had a really good side and we brought each other on.
“We all wanted the same thing and we had really good coaches as well, so I don’t think it’s any surprise there’s a few Stanningley players coming through.
“Jordan and Ashton are outstanding players for their age and I am just looking to emulate what they are doing for the first team at the minute.”