Inclusion Criteria:  1a) Key informants (for interviews)  Members of the community/advisory groups, community health centers, or faith-based network members (e.g., Pink and Black, Faces of Faith). English speaking adults.  (1b) Breast cancer survivors and relatives (for interviews)  Self-identify as Black or African American Age 18 and over English speaking Female breast cancer survivor status post curative antineoplastic treatment (except ongoing hormonal treatment) with no evidence of disease, OR a first degree blood relative (parent, child, or full sibling), of any gender, of a so defined breast cancer survivor Self-report ever using a smart phone  (2) Breast cancer survivors and relatives (for user testing/interviews)  Self-identify as Black or African American Age 18 and over English speaking Female breast cancer survivor status post curative antineoplastic treatment (except ongoing hormonal treatment) with no evidence of disease, OR a first degree blood relative (parent, child, or full sibling), of any gender, of a so defined breast cancer survivor Self-report willing/able to download the app for testing on a smart phone Self-report willing/able to meet via Zoom for interview  (3) Breast cancer survivors and relatives/"buddies" (for pilot testing)  Self-identify as Black or African American Age 18 and over English speaking Breast cancer survivor status post curative antineoplastic treatment (except ongoing hormonal treatment) with no evidence of disease, OR a blood relative, of any gender, of a so defined breast cancer survivor Self-report willing/able to participate with a blood relative in survivor relative dyad Self-report willing/able to download the app for use on a smart phone Self-report willing/able to meet via Zoom for instructions and interview  Exclusion Criteria:  (1a) Key informants (for interviews)  --None  (1b) Breast cancer survivors and relatives (for interviews)  Requires medically supervised physical activity (Physical Activity Readiness Question for Everyone, PAR-Q+, Question 7) Pregnant women  (2) Breast cancer survivors and relatives (for user testing/interviews)  Requires medically supervised physical activity (Physical Activity Readiness Question for Everyone, PAR-Q+, Question 7) Pregnant women  (3) Breast cancer survivors and relatives/"buddies" (for pilot testing)  Meets exclusion criterion of the Modified Physical Activity Readiness Questionnaire (PAR-Q) (modified) Participated in interviews or user testing in prior phases of the study